1. Field of the Invention
The present invention relates to a method of conveying toner material from a toner refill container in an electrographic printer or copier. A toner refill container is inserted into an electrographic printer or copier and emptied via an opening. Further, the invention relates to a device for inserting a toner refill container into an electrographic printer or copier as well as to an associated toner refill container.
2. Description of the Related Art
In electrophotographic printers or copiers, a latent charge image is generated on a light-sensitive photoconductor material, a photoconductor drum or a photoconductor belt. Subsequently, this charge image is inked with electrically charged toner in a developer station of the printer or copier. The inked toner image is then transferred onto a carrier material, e.g. paper, and fixed thereon.
A one-component developer or a two-component developer is used for developing the latent charge image in the developer station. The one-component developer only contains toner particles; the two-component developer contains a mixture of toner particles and carrier particles. With a two-component developer, the toner particles are electrically charged by moving the two-component developer mixture. For the one-component developer, the charging of the toner particles takes place via charge transport, for example, from a carrier drum.
The amount of toner required for generating the toner image has to be supplied to the developer station so that further toner images can be generated. In known printers or copiers, an intermediate toner reservoir in which toner material is intermediately stored is provided near the developer station, toner material being conveyed from this reservoir into the developer station depending on need or, respectively, on consumption.
In known printers or copiers, the toner material is filled from handy refill containers via an opening directly into the reservoir or from a remotely arranged refill container through a transport system into the reservoir. In known printers or copiers, the reservoir arranged near the developer station has a level sensor. In the case of a minimum filling level, toner material has to be supplied to the reservoir from the refill container. This is, for example, effected by emptying a refill container into the reservoir. In other known arrangements, closed containers in the form of bottles or cartridges that are filled with toner material are adapted to an opening in the reservoir. The bottle or cartridge is opened by pulling a slide and/or breaking a tab, as a result whereof the toner material can drop into the reservoir.
However, these solutions for refilling toner material into the reservoir involve a high risk of contamination for an operator and the surrounding of the reservoir when filling in the toner material and when removing the emptied refill container. A low weight and a small structural size of the bottles and/or the cartridges indeed allows a simple and safe handling during refilling of the reservoir, however, in the case of a high toner consumption frequent refilling of the reservoir is required, as a result whereof extended machine downtimes occur and the operator is highly stressed.
U.S. Pat. No. 4,990,964 and U.S. Pat. No. 5,074,342 disclose a toner refill container and a device for the non-contaminating change of such a refill container in a toner conveying means of a printer or copier. When needed, toner material is transported from a toner refill container arranged remotely from the developer station into the reservoir via a hose by means of suction air. A vertically displaceable suction nozzle immerses via an opening arranged in the top of the toner container and sucks out toner material. A special shape of the toner container and a laterally mounted shaking means provide an almost complete emptying of the container. For changing the toner refill container, the suction nozzle is extracted from the container. The opening is always arranged on the top of the toner container, as a result whereof spilling of toner is avoided. However, the conveying capacity is heavily dependent on the filling level in the toner container. When the filling level decreases, the conveying capacity of toner material likewise decreases so that the printing operation is interrupted in the case of a low toner filling level in the toner refill container and a simultaneous high toner demand in the developer station. Further, the shaker means creates disturbing sounds.
U.S. Pat. No. 5,915,154 discloses an apparatus for conveying toner material from a toner refill container by means of a suction/pressure unit that projects into the refill container. Toner material is mixed with gas with the aid of the suction/pressure unit so that the toner material to be sucked in is mixed to a powder/gas mixture, as a result whereof the removal of the finely powdered toner material out of the refill container is facilitated. However, this known apparatus, too, has the problem that when the filling level in the refill container decreases, the conveying capacity likewise decreases, this resulting in the already described interruption of the printing process as a consequence of too little re-supply of toner material.